The invention relates to a rail wheel.
In the known rail wheels, the wheel brake disks connected to the wheel body on both sides are fastened to the wheel body by a plurality of fastening elements, primarily throughbolts, distributed over the circumference.
In this case, the wheel brake disks bear with integrally formed cooling ribs, centering and fastening eyes directly against the wheel body, to be precise against a circumferential wheel web which connects a wheel hub to an outer race.
However, considerable operationally induced problems arise due to the direct contact of the wheel brake disks with the wheel body.
For example, during a braking operation, as a result of the axial temperature gradients which occur, considerable excessive rises in the surface pressure occur radially on the outside of the wheel brake disk between the wheel web and the contact regions. (If the respective brake disk were not bolted to the wheel body, it would assume the shape of a Belleville spring).
In addition, the annular wheel brake disks have the tendency to deform in an opposed plate-like manner due to internal tensile stresses in the frictional surfaces, which stresses occur due to high thermal loading.
Excessive rises in the surface pressures in the radially inner contact regions then occur in the cold state.
Due to a thermally induced “breathing” of the wheel brake disk, i.e. a radial contraction and expansion at intervals, a “frictional sliding” occurs in the contact regions during every braking operation.
Due to the above-mentioned excessive rises in the surface pressures, especially at high braking powers, scoring occurs between the wheel brake disks and the wheel body in the region of the contact regions or local plastic deformation occurs in the wheel web, and this may lead in the long term to damage, such as the formation of cracks, in the wheel.